Wednesday, January 14, 2009

HIV with Neurological Findings

(Left: Cerebral Toxoplasmosis in AIDS)

(Left: PML seen on MRI)

A general approach to a patient with HIV and neurologic findings will be discussed here. We also talked about headaches and a good approach + some links can be found here. It is crucial to get a detailed history - including past CD4 counts/viral loads, a history of antiretroviral therapy and adherence to therapy, and a history of opportunistic infections.

After a detailed history and physical exam are performed, imaging of the head is often done. We typically categorize diseases into Central Nervous System lesions with a mass effect and those with no mass effect. Of note, contrast should be used to obtain the best images, and MRI is preferred over CT.

Mass Effect:

  • Toxoplasmosis: can present with fever, headache, focal deficits, or seizures. Multiple ring enhancing lesions are visualized, and CD4 counts are typically less than 100.

  • Primary CNS Lymphoma: can present with focal deficits, confusion, seizure, and constitutional symptoms. There can be one or more lesions, and they may or may not ring enhance (may look like Toxo).

  • Abscess: many pathogens can do this including Staphylococcus, Streptococcus, Aspergillus, Nocardia, plus some really strange ones like cryptococcomas, tuberculomas, and syphilitic gummas.

No Mass Effect:

  • Progressive multifocal leukoencephalopathy: As the name implies, there are progressive neurologic deficits in this condition. Hemiparesis, ataxia, aphasia, and mental status changes. It is from reactivation of the JC virus, which can be detected in the CSF. Look for asymmetric subcortical and periventricular demylination.

  • HIV Encephalopathy: Radiographically, this is more symmetric and diffuse compared to PML. Patients will have mental status changes and likely disordered movement.

  • CMV Encephalitis: This represents reactivation of CMV seen when CD4 counts drop below 50. Either subcortical changes or ventricular enlargement are visualized.
  • Meningitis: think the usual bacterial causes (Streptococcus, Meningococcus, H. flu, Listeria) to more unusual etiologies like cryptococcus, and tuberculosis.

Here is a link on the general managment of a new HIV infection.

These are the most recent guidelines on the treatment of Opportunistic Infections.

Here is a good review on PML.

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